TQ2440开发板request_irq中断注册失败（-22）原因分析（一）
一.驱动代码
uiVal = readl(S3C2410_EXTINT0);
uiVal &= ~(0x1<<18);
// uiVal |= (0x1<<18);
uiVal |= (0x1<<17);
writel(uiVal, S3C2410_EXTINT0);
ret = request_irq(IRQ_EINT4t7, kobox_gpio_irq_handle, IRQF_SHARED, "key2", (void *)&nouse);
if(ret)
{
printk("[func:%s][line:%d] request_irq failed, ret:%d!\n", __FUNCTION__,__LINE__,ret);
}
二.执行结果
[\u@\h \W]# insmod key.ko #####enter key_drv_init! #####[func:request_threaded_irq][line:1504] [func:request_irq_for_gpio][line:282] request_irq failed, ret:-22! #####key_drv_init ok!
三. 原因分析
（1）dm9000.c中有irq 20的注册
#####[func:request_threaded_irq][line:1493], irq:55CPU: 0 PID: 985 Comm: ifconfig Not tainted 3.16.1-svn57 #27
[<c011b1a8>] (unwind_backtrace) from [<c0118a38>] (show_stack+0x10/0x14)
[<c0118a38>] (show_stack) from [<c0152ff0>] (irq_to_desc+0x2c/0x54)
[<c0152ff0>] (irq_to_desc) from [<c015596c>] (irq_get_irq_data+0x8/0xc)
[<c015596c>] (irq_get_irq_data) from [<c02dbb88>] (s3c_irq_unmask+0x44/0x74)
[<c02dbb88>] (s3c_irq_unmask) from [<c01556b4>] (irq_enable+0x44/0x54)
[<c01556b4>] (irq_enable) from [<c0156170>] (irq_startup+0x64/0x68)
[<c0156170>] (irq_startup) from [<c01543fc>] (__setup_irq+0x1f8/0x4fc)
[<c01543fc>] (__setup_irq) from [<c0154940>] (request_threaded_irq+0xf4/0x1e4)
[<c0154940>] (request_threaded_irq) from [<c0385684>] (dm9000_open+0x70/0x134)
[<c0385684>] (dm9000_open) from [<c0430ae0>] (__dev_open+0xb8/0x114)//看来这里调用了中断
[<c0430ae0>] (__dev_open) from [<c04308b0>] (__dev_change_flags+0x90/0x16c)
[<c04308b0>] (__dev_change_flags) from [<c04309ac>] (dev_change_flags+0x18/0x48)
[<c04309ac>] (dev_change_flags) from [<c048cf88>] (devinet_ioctl+0x6d0/0x778)
[<c048cf88>] (devinet_ioctl) from [<c041d130>] (sock_ioctl+0x68/0x298)
[<c041d130>] (sock_ioctl) from [<c01b41bc>] (do_vfs_ioctl+0x7c/0x5f4)
[<c01b41bc>] (do_vfs_ioctl) from [<c01b476c>] (SyS_ioctl+0x38/0x5c)
[<c01b476c>] (SyS_ioctl) from [<c0115840>] (ret_fast_syscall+0x0/0x2c)
#####[func:irq_to_desc][line:279], [irq==20] NR_IRQS:111
dm9000 dm9000 eth0: link down
（2）不只是上面的dm9000有注册irq 20，将dm9000.c中的中断注册注掉，仍然有irq 20的注册
S3C2440: IRQ Support
#####[func:irq_to_desc][line:279], [irq==20] NR_IRQS:111
#####[func:irq_to_desc][line:279], [irq==20] NR_IRQS:111
#####[func:irq_to_desc][line:279], [irq==20] NR_IRQS:111
#####[func:irq_to_desc][line:279], [irq==20] NR_IRQS:111
#####[func:irq_to_desc][line:279], [irq==20] NR_IRQS:111
#####[func:irq_to_desc][line:279], [irq==20] NR_IRQS:111
irq: clearing pending status 00080000
#####[func:irq_to_desc][line:279], [irq==20] NR_IRQS:111
#####[func:irq_to_desc][line:279], [irq==20] NR_IRQS:111
#####[func:irq_to_desc][line:279], [irq==20] NR_IRQS:111
#####[func:irq_to_desc][line:279], [irq==20] NR_IRQS:111
root@ubuntu:/mnt/shared/linux-3.16.1/drivers# grep "IRQ Support" ./ -r
Binary file ./built-in.o matches
Binary file ./irqchip/built-in.o matches
Binary file ./irqchip/irq-s3c24xx.o matches
./irqchip/irq-s3c24xx.c: pr_info("S3C2412: IRQ Support\n");
./irqchip/irq-s3c24xx.c: pr_info("S3C2416: IRQ Support\n");
./irqchip/irq-s3c24xx.c: pr_info("S3C2440: IRQ Support\n");
./irqchip/irq-s3c24xx.c: pr_info("S3C2442: IRQ Support\n");
./irqchip/irq-s3c24xx.c: pr_info("S3C2443: IRQ Support\n");
root@ubuntu:/mnt/shared/linux-3.16.1/drivers#
打印：
NR_IRQS:111
S3C2440: IRQ Support
####################################[s3c2440_init_irq][980]
####################################[s3c2440_init_irq][986]
#####[func:irq_to_desc][line:279], [irq==20] NR_IRQS:111
#####[func:irq_to_desc][line:279], [irq==20] NR_IRQS:111
#####[func:irq_to_desc][line:279], [irq==20] NR_IRQS:111
#####[func:irq_to_desc][line:279], [irq==20] NR_IRQS:111
#####[func:irq_to_desc][line:279], [irq==20] NR_IRQS:111
#####[func:irq_to_desc][line:279], [irq==20] NR_IRQS:111
####################################[s3c2440_init_irq][995]
irq: clearing pending status 00080000
#####[func:irq_to_desc][line:279], [irq==20] NR_IRQS:111
#####[func:irq_to_desc][line:279], [irq==20] NR_IRQS:111
#####[func:irq_to_desc][line:279], [irq==20] NR_IRQS:111
#####[func:irq_to_desc][line:279], [irq==20] NR_IRQS:111
####################################[s3c2440_init_irq][999]
irq: clearing pending status 00000003
irq: clearing pending status 00000002
####################################[s3c2440_init_irq][1004]
将如下部分注掉后，key.ko中注册正常： s3c24xx_init_intc(NULL, &init_eint[0], s3c_intc[0], 0x560000a4);
函数代码：
void __init s3c2440_init_irq(void)
{
pr_info("S3C2440: IRQ Support\n");
printk("####################################[%s][%d]\n", __FUNCTION__, __LINE__);
#ifdef CONFIG_FIQ
init_FIQ(FIQ_START);
#endif
printk("####################################[%s][%d]\n", __FUNCTION__, __LINE__);
#if 1
s3c_intc[0] = s3c24xx_init_intc(NULL, &init_s3c2440base[0], NULL,
0x4a000000);
if (IS_ERR(s3c_intc[0])) {
pr_err("irq: could not create main interrupt controller\n");
return;
}
printk("####################################[%s][%d]\n", __FUNCTION__, __LINE__);
#if 0
s3c24xx_init_intc(NULL, &init_eint[0], s3c_intc[0], 0x560000a4);
#endif
printk("####################################[%s][%d]\n", __FUNCTION__, __LINE__);
s3c_intc[1] = s3c24xx_init_intc(NULL, &init_s3c2440subint[0],
s3c_intc[0], 0x4a000018);
#endif
printk("####################################[%s][%d]\n", __FUNCTION__, __LINE__);
}
#endif
但是会出现如下打印：
s3c-sdi s3c2440-sdi: can't get card detect irq.
------------[ cut here ]------------
WARNING: CPU: 0 PID: 1 at kernel/irq/manage.c:1325 __free_irq+0x108/0x178()
Trying to free already-free IRQ 64
Modules linked in:
CPU: 0 PID: 1 Comm: swapper Not tainted 3.16.1-svn57 #35
[<c011b1a8>] (unwind_backtrace) from [<c0118a38>] (show_stack+0x10/0x14)
[<c0118a38>] (show_stack) from [<c0124f24>] (warn_slowpath_common+0x60/0x80)
[<c0124f24>] (warn_slowpath_common) from [<c0124fd8>] (warn_slowpath_fmt+0x30/0x40)
[<c0124fd8>] (warn_slowpath_fmt) from [<c0154de4>] (__free_irq+0x108/0x178)
[<c0154de4>] (__free_irq) from [<c0154e98>] (free_irq+0x44/0x80)
[<c0154e98>] (free_irq) from [<c03dfa84>] (s3cmci_probe+0x250/0x57c)
[<c03dfa84>] (s3cmci_probe) from [<c03234fc>] (platform_drv_probe+0x1c/0x4c)
[<c03234fc>] (platform_drv_probe) from [<c0321e0c>] (driver_probe_device+0x88/0x224)
[<c0321e0c>] (driver_probe_device) from [<c0322034>] (__driver_attach+0x8c/0x90)
[<c0322034>] (__driver_attach) from [<c03209ac>] (bus_for_each_dev+0x78/0x9c)
[<c03209ac>] (bus_for_each_dev) from [<c0321014>] (bus_add_driver+0xe4/0x1d4)
[<c0321014>] (bus_add_driver) from [<c03225b8>] (driver_register+0x58/0xf8)
[<c03225b8>] (driver_register) from [<c01089f8>] (do_one_initcall+0x84/0x1e4)
[<c01089f8>] (do_one_initcall) from [<c06165c8>] (kernel_init_freeable+0xf4/0x1bc)
[<c06165c8>] (kernel_init_freeable) from [<c04d5000>] (kernel_init+0x8/0x10c)
[<c04d5000>] (kernel_init) from [<c01158d0>] (ret_from_fork+0x14/0x24)
---[ end trace 31de2d25f8e2a307 ]---
s3c-sdi: probe of s3c2440-sdi failed with error -2
TCP: cubic registered
NET: Registered protocol family 17
将如下内容打开： s3c24xx_init_intc(NULL, &init_eint[0], s3c_intc[0], 0x560000a4);
void __init s3c2440_init_irq(void)
{
pr_info("S3C2440: IRQ Support\n");
printk("####################################[%s][%d]\n", __FUNCTION__, __LINE__);
#ifdef CONFIG_FIQ
init_FIQ(FIQ_START);
#endif
printk("####################################[%s][%d]\n", __FUNCTION__, __LINE__);
#if 1
s3c_intc[0] = s3c24xx_init_intc(NULL, &init_s3c2440base[0], NULL,
0x4a000000);
if (IS_ERR(s3c_intc[0])) {
pr_err("irq: could not create main interrupt controller\n");
return;
}
printk("####################################[%s][%d]\n", __FUNCTION__, __LINE__);
#if 1
s3c24xx_init_intc(NULL, &init_eint[0], s3c_intc[0], 0x560000a4);
#endif
printk("####################################[%s][%d]\n", __FUNCTION__, __LINE__);
s3c_intc[1] = s3c24xx_init_intc(NULL, &init_s3c2440subint[0],
s3c_intc[0], 0x4a000018);
#endif
printk("####################################[%s][%d]\n", __FUNCTION__, __LINE__);
}
#endif
而将 struct s3c_irq_data init_eint[32] 做如下修改：
原因：注册EINT0\1\2都是正常的，但是注册EINT4-7失败，而这里没有0\1\2\3，这就是和EINT4-7的差异
static struct s3c_irq_data init_eint[32] = {
{ .type = S3C_IRQTYPE_NONE, }, /* reserved */
{ .type = S3C_IRQTYPE_NONE, }, /* reserved */
{ .type = S3C_IRQTYPE_NONE, }, /* reserved */
{ .type = S3C_IRQTYPE_NONE, }, /* reserved */
#if 0
{ .type = S3C_IRQTYPE_EINT, .parent_irq = 4 }, /* EINT4 */
{ .type = S3C_IRQTYPE_EINT, .parent_irq = 4 }, /* EINT5 */
{ .type = S3C_IRQTYPE_EINT, .parent_irq = 4 }, /* EINT6 */
{ .type = S3C_IRQTYPE_EINT, .parent_irq = 4 }, /* EINT7 */
{ .type = S3C_IRQTYPE_EINT, .parent_irq = 5 }, /* EINT8 */
#else
{ .type = S3C_IRQTYPE_NONE, }, /* reserved */
{ .type = S3C_IRQTYPE_NONE, }, /* reserved */
{ .type = S3C_IRQTYPE_NONE, }, /* reserved */
{ .type = S3C_IRQTYPE_NONE, }, /* reserved */
#endif
{ .type = S3C_IRQTYPE_EINT, .parent_irq = 5 }, /* EINT9 */
{ .type = S3C_IRQTYPE_EINT, .parent_irq = 5 }, /* EINT10 */
{ .type = S3C_IRQTYPE_EINT, .parent_irq = 5 }, /* EINT11 */
{ .type = S3C_IRQTYPE_EINT, .parent_irq = 5 }, /* EINT12 */
{ .type = S3C_IRQTYPE_EINT, .parent_irq = 5 }, /* EINT13 */
{ .type = S3C_IRQTYPE_EINT, .parent_irq = 5 }, /* EINT14 */
{ .type = S3C_IRQTYPE_EINT, .parent_irq = 5 }, /* EINT15 */
{ .type = S3C_IRQTYPE_EINT, .parent_irq = 5 }, /* EINT16 */
{ .type = S3C_IRQTYPE_EINT, .parent_irq = 5 }, /* EINT17 */
{ .type = S3C_IRQTYPE_EINT, .parent_irq = 5 }, /* EINT18 */
{ .type = S3C_IRQTYPE_EINT, .parent_irq = 5 }, /* EINT19 */
{ .type = S3C_IRQTYPE_EINT, .parent_irq = 5 }, /* EINT20 */
{ .type = S3C_IRQTYPE_EINT, .parent_irq = 5 }, /* EINT21 */
{ .type = S3C_IRQTYPE_EINT, .parent_irq = 5 }, /* EINT22 */
{ .type = S3C_IRQTYPE_EINT, .parent_irq = 5 }, /* EINT23 */
};
果然是可以注册成功的
综上所述，tq2440中request_irq注册20号中断（EINT4-7）失败的直接原因是：
init_eint[32] 中对其进行了初始化
但是如果将dm9000.c中注掉的代码打开，在insmod key.ko后，再ifconfig eth0，会出现eth0 open失败的情况：
[\u@\h \W]# ifconfig eth0 up
####################################[dm9000_open][1331]
#####[func:request_threaded_irq][line:1493], irq:55
ifconfig: SIOCSIFFLAGS: Resource temporarily unavailable
这说明：
dm9000.c中对20号中断的注册，和key.ko中的注册，还是有冲突的
为什么有冲突呢？共享中断如何共享、如何注册呢？后面进一步分析。